High efficiency signaling with minimum spacecraft hardware

Abstract

A method is disclosed for efficiently transmitting large numbers of data channels through a satellite (24). The method uses a block encoder (28) that encodes the data channels with a block code to produce an encoded uplink data stream. A modulator (30) modulates the encoded uplink data stream. A transmit antenna (32) then sends the resultant modulated uplink data stream (34) to the satellite (24). The satellite uses a satellite demodulator (48) and a switch (50) to produce an internal data stream consisting of selected data channels in the uplink data stream (34). The internal data stream is fed into a convolutional encoder (52). The output of the convolutional encoder (52) is connected to a satellite modulator (54). The satellite transmit antenna (56) then sends the resultant modulated downlink data stream (58) to a receiver.

What is claimed is: 
     
       1. A method for communicating input data channels through a satellite, the method comprising: (a) block encoding input data channels to produce a block encoded uplink data stream;   (b) modulating said block encoded uplink data stream to produce a modulated uplink data stream;   (c) transmitting said modulated uplink data stream to a satellite;   (d) demodulating said modulated uplink data stream in said satellite to produce a recovered block encoded uplink data stream;   (e) convolutionally encoding in said satellite said recovered block encoded uplink data stream without decoding the recovered block encoded uplink data stream to produce a concatenated coded downlink data stream;   (f) modulating said concatenated coded downlink data stream to produce a modulated downlink data stream;   (g) transmitting said modulated downlink data stream to a receiver.   
     
     
       2. The method of claim 1, further comprising the steps of: (h) demodulating said modulated downlink data stream in said receiver to generate a reproduced concatenated coded downlink data stream;   (i) convolutionally decoding said reproduced concatenated coded downlink data stream in said receiver to generate a reproduced recovered block encoded uplink data stream;   (j) block decoding said reproduced recovered block encoded uplink data stream in said receiver to produce output data channels.   
     
     
       3. The method of claim 1, wherein the modulation of step (b) is QPSK. 
     
     
       4. The method of claim 1, wherein the modulation of step (f) is QPSK. 
     
     
       5. The method of claim 1, wherein the modulation of step (b) is BPSK. 
     
     
       6. The method of claim 1, wherein the modulation of step (f) is BPSK. 
     
     
       7. The method of claim 1, wherein the demodulation of step (d) uses a hard-decision technique. 
     
     
       8. The method of claim 1, wherein the block encoding of step (a) uses a Reed-Solomon code. 
     
     
       9. The method of claim 2, wherein the convolutional decoding of step (i) uses a Viterbi decoder. 
     
     
       10. The method of claim 1 wherein the modulation of steps (b) and (f) comprises CDMA modulation and wherein the demodulation of step (d) comprises CDMA demodulation. 
     
     
       11. A method for communicating input data channels through a satellite, the method comprising: (a) block encoding input data channels to produce a plurality of block encoded uplink data streams;   (b) modulating said plurality of block encoded uplink data streams to produce a plurality of modulated uplink data streams;   (c) transmitting said plurality of modulated uplink data streams to said satellite;   (d) demodulating said plurality of modulated uplink data streams in said satellite to produce at least one recovered block encoded uplink data stream;   (e) switching said at least one recovered block encoded uplink data stream to a plurality of internal data streams, each of said plurality of internal data streams associated with an individual convolutional encoder;   (f) convolutionally encoding each of said plurality of internal data streams without block decoding said recovered block encoded uplink data stream in said satellite to produce a plurality of concatenated coded downlink data streams;   (g) modulating each of said plurality of concatenated coded downlink data streams to produce a plurality of modulated downlink data streams;   (h) transmitting each of said plurality of modulated downlink data streams.   
     
     
       12. The method of claim 11, further comprising the steps of: (i) demodulating at least one of said plurality of modulated downlink data streams in a receiver to generate a recovered concatenated coded downlink data stream;   (j) convolutionally decoding said recovered concatenated coded downlink data stream in said receiver to generate a recovered internal data stream;   (k) block decoding said recovered internal data stream in said receiver to produce output data channels.   
     
     
       13. The method of claim 11, wherein the modulation of step (b) is QPSK. 
     
     
       14. The method of claim 11, wherein the modulation of step (g) is QPSK. 
     
     
       15. The method of claim 11, wherein the modulation of step (b) is BPSK. 
     
     
       16. The method of claim 11, wherein the modulation of step (g) is BPSK. 
     
     
       17. The method of claim 11, wherein the demodulation of step (d) uses a hard-decision technique. 
     
     
       18. The method of claim 11, wherein the block encoding of step (a) uses a Reed-Solomon code. 
     
     
       19. The method of claim 12, wherein the convolutional decoding of step (j) uses a Viterbi decoder. 
     
     
       20. The method of claim 11, wherein the modulation of steps (b) and (f) comprises CDMA modulation and wherein the demodulation of step (d) comprises CDMA demodulation.